The inventors have proposed a three-dimensional display apparatus which allows many people can simultaneously observe an image by naked eyes in all directions, namely, 360 degrees around the image like a multiplex hologram (refer to Non-Patent Documents 1, 2, and 3). The apparatus is configured in such a manner that one-dimensional light source arrays are composed of one-dimensional light-emitting elements such as LEDs capable of high-speed modulation and vertically arranged in a line, and the light source arrays are rotated inside a cylindrical parallax barrier. This apparatus is characterized by its capability of displaying an image at narrower parallax intervals than ever by rotating the cylindrical parallax barrier in a direction opposite to that of the light source array. As a three-dimensional display apparatus used in carrying out the present invention, it is confirmed that a stereoscopic image can be actually displayed and observed in all directions by this proposed apparatus (refer to Non-patent Document 4).
Japanese Patent Publication No. 2003-195214 (Patent Document 1) has proposed a stereoscopic display system that uses a parallax barrier and a light-emitting array for rotational scanning.
Japanese Patent Publication No. 10-97013 (Patent Document 2) has disclosed another example of a stereoscopic image display system. This stereoscopic image display system uses a three-dimensional display apparatus to present a stereoscopic image, which can be visually recognized by naked eyes, to people located outside the three-dimensional image display apparatus having a cylindrical image display surface or plane defined therein. The image display surface is formed of a plurality of pixels which are respectively configured to emit light of different colors and brightness as defined according to an angle at which the pixel is viewed on a horizontal plane.    Non-Patent Document 1: Tomohiro Endo and Makoto Sato, “Cylindrical Real-Time 3-D Display with Scanned 1-D Light Source Arrays”, Journal of the Institute of Image Information and Television Engineers of Japan, Vol. 53, No. 3, pp. 399-404, (1999)    Non-Patent Document 2: Tomohiro Endo, Yoshihiro Kajiki, Toshio Honda, and Makoto Sato, “A Cylindrical 3-D Display Observable from All Directions”, 3-D Image Conference '99 Papers, pp. 99-104 (1999)    Non-Patent Document 3: Tomohiro Endo, Yoshihiro Kajiki, Toshio Honda, and Makoto Sato, “Cylindrical 3-D Display Observable from All Directions”, Transactions of The Institute of Electronics, Information and Communication Engineers D-II, Vol. J84-D-II, No. 6, pp 1003-1011, (2001)    Non-Patent Document 4: Tomohiro Endo, Toshio Honda, “Cylindrical 3-D Video Display—Color Video Display System—”, 3-D Image Conference 2002 Papers, pp. 89-92 (2002)    Patent Document 1: Japanese Patent Publication No. 2003-195214 (Applicant: Seiko Epson Corporation)    Patent Document 2: Japanese Patent Publication No. 10-97013 (Applicant: Futaba Corporation)